Extreme Engine Tech, Technosquare’s Monster Naturally Aspirated Toyota 4AG


ARP Studs
High strength ARP studs allow higher torque and more clamping load for the cylinder head and main caps.  Studs are also inherently stronger than bolts and unlike the stock torque to yield bolts, they can be reused.  Special hardened washers and high strength nuts are used as well but are not shown.

CBY, a Japanese 4AG tuner supplied this billet stroker crank.  At 83mm of stroke, up 6mm from the stock 77mm, this crank punches the 4AG out to 1800cc when paired with 83mm big bore pistons.  The stroker motor is good for 30 more hp over the standard 1600cc engine.  The stock 4AG crank is also a weak point on the engine.  The early AE86/AE82/AW11 version of the 4AG had smaller rod journals at 40mm and were very weak.  The stock crank fails at the #3 rod journal when the revs are pushed beyond 8000 rpm and the power above 180 hp.  The CBY crank is made of high strength 4340 high nickle alloy and uses the larger diameter 42mm late rod journal size.  The CBY crank has generous fillets and chamfered oil passages and is post machining heat treated and shotpeened for extra durability.  If you are building your own low buck 4AG, it is advisable to run the later 1988 and up supercharged MR2/AE92 crank, rods and bearings.  This crank is much stronger.

CBY rods are H beam and feature super strong rod bolts and floating pin bushings.  They are machined from 4340 alloy billets.  The piston pin uses the larger late post 1988 4AG 20mm diameter as the smaller 18mm early pins were prone to distort and wear the rod bushing at high RPM.  The CBY rods are shotpeened for greater fatigue strength.

Greddy cam drive belt is heavy duty and Kevlar reinforced for extra strength and durability at high rpm.


HKS supplied this MLS (Multi Layer Steel) head gasket, important to ensure sealing at high compression ratios.  MLS gaskets require good block and cylinder deck preparation to obtain a good reliable seal.

Stay tuned, in part two we will dig deeper into the guts of the ultimate naturally aspirated 4AG.



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